Storage tank



FIG. 1 is a right, rear perspective view of a storage tank showing my new design;

FIG. 2 is a left, front perspective view thereof;

FIG. 3 is a front view of the storage tank of FIG. 1.

FIG. 4 is a rear view of the storage tank of FIG. 1; and,

FIG. 5 is a top view of the storage tank of FIG. 1.

The bottom of the storage tank is flat and devoid of surface ornamentation, and therefore not shown. 

The ornamental design for a storage tank, as shown and described. 